Association between prehospital time and injury severity in traffic crash patients

• Longer on-scene time was associated with higher trauma severity in traffic crashes. • Associations between on-scene time and injury severity differed by age group. • Longer on-scene time was associated with severe injuries across multiple body regions. • On-scene time likely reflects injury complexity and patient acuity. • Results are consistent with the importance of early injury severity recognition in EMS care. This study aimed to examine the association between on-scene time and trauma severity, with particular attention to differences across age groups and anatomical injury regions among patients injured in traffic crashes. We conducted a retrospective cohort study by linking emergency medical services (EMS) prehospital records with hospital-based trauma registry data from a single Level 1 trauma centre in metropolitan Taipei between 2016 and 2022. Traffic crash patients transported by EMS were included. Prehospital time was disaggregated into response time, on-scene time, and transport time. Injury severity was assessed using the Injury Severity Score (ISS), with ISS ≥ 9 defined as severe injury. Multivariable logistic regression models were used to evaluate associations between prehospital time components and injury severity. Additional analyses were stratified by age group and anatomical injury region. Among 5,022 patients, 1,858 (37.0%) sustained severe injuries. Longer on-scene time was strongly associated with higher injury severity; each additional minute on scene was associated with a 10.1% increase in the odds of severe injury (adjusted odds ratio AOR = 1.101; 95% CI, 1.085–1.117). Older age, poor consciousness, pedestrian involvement, and late-night crashes were also associated with severe injury. Age- and region-stratified analyses demonstrated consistent associations between longer on-scene time and higher severity (AIS ≥ 3) for head, thoracic, abdominal, and extremity injuries, with more pronounced associations among older adults. Longer on-scene time is closely associated with trauma severity and likely reflects greater injury complexity and patient acuity rather than a direct causal effect. Given the observational nature of this study, the findings should be interpreted cautiously and may be influenced by reverse causation and confounding by indication. These results highlight the importance of early severity recognition, appropriate triage, and minimizing avoidable delays while ensuring essential life-saving interventions in prehospital trauma care.